Enhanced Photocatalytic Hydrogen Evolution of 2D Cu−In−Zn−S Nanobelts Through Coupling With Ni 9 S 8 Nanoparticles

Ensuring broad‐spectrum visible‐light absorption and efficient electron extraction is essential for enhancing the efficiency of photocatalytic hydrogen production. To achieve this, manipulating carrier dynamics through cocatalyst heterojunction engineering has attracted considerable concern. However, conventional narrow‐bandgap Cu–In–Zn–S (CIZS) nanocrystals (NCs) typically exhibit limited photocatalytic activity due to severe exciton annihilation. Herein, two‐dimensional (2D) CIZS nanobelts (NBs) were coupled with Ni 9 S 8 cocatalyst to construct a library of CIZS/Ni 9 S 8 Schottky heterojunctions synthesized via a combined colloidal one‐pot and hot‐injection strategy. As anticipated, the CIZS/2.0%Ni 9 S 8 heterojunction displayed the optimal photocatalytic hydrogen evolution activity of 2.75 mmol g −1 h −1 , ≈3.31 times higher than that of pristine CIZS NBs (0.83 mmol g −1 h −1 ). Experimental results uncovered that the enhanced photocatalytic performance originated from the formation of the CIZS/2.0%Ni 9 S 8 Schottky heterojunction, which facilitated efficient charge transfer from CIZS NBs to Ni 9 S 8 and hindered the return of electrons. Moreover, Ni 9 S 8 serves as active catalytic sites, significantly accelerating surface proton reduction reactions. This study provides valuable insights into the rational design and precise synthesis of colloidal multinary Cu‐based chalcogenide heterojunctions for efficient photocatalytic energy conversion.